A previous version of this article stated that energy-related carbon dioxide emissions fell in nearly every state, without specifying if that decline was in absolute or per capita terms. From 2005 to 2013, state emissions per capita fell in 48 states (including the District of Columbia) and rose in 3 states. In absolute terms, emissions fell in 42 states and rose in 9 states.

The United States has a diverse energy landscape that is reflected in differences in state-level emissions profiles. Since 2005, energy-related carbon dioxide (CO2) emissions fell in 48 states (including the District of Columbia) and rose in 3 states, on a per capita basis. EIA's latest analysis of state-level energy-related CO2 emissions includes data in both absolute and per capita terms, including details by fuel and by sector.

This analysis measures emissions released at the location where fossil fuels are consumed. Therefore, to the extent that fuels are used in one state to generate electricity that is consumed in another state, emissions are attributed to the former rather than the latter. An analysis attributing emissions to the consumption of electricity, rather than to the production of electricity, would yield different results.

The 10 states with the highest levels of energy-related CO2 emissions in 2013 accounted for half of the U.S. total. These 10 states also have large populations and account for slightly more than half (53%) of the nation's total population. California was the second-highest emitter in absolute terms (353 million metric tons of carbon dioxide, or MMmt CO2), behind only Texas (641 MMmt CO2). But California was also the fourth-lowest emitter on a per capita basis, behind the District of Columbia, New York, and Vermont. Relatively small states such as Wyoming and North Dakota had much higher levels of per capita emissions in 2013, nearly seven times and five times the national average, respectively.

Energy-related CO2 emissions come from coal, petroleum, and natural gas consumed within a state to produce electricity (38% of U.S. total), to transport goods or people (33%), to operate industrial processes (18%), or to directly fuel equipment in residential and commercial buildings (10%). The consumption levels by fuel and by sector vary considerably by state. For example, coal consumption accounted for 78% of energy-related CO2 emissions in West Virginia in 2013, while coal only accounted for 1% of emissions in California.

Consumption of petroleum accounted for more than 90% of energy-related CO2 emissions in two states, Hawaii and Vermont, but for different reasons. In both states, emissions from the transportation sector accounted for more than 50% of energy-related emissions. In Vermont, the nonelectric (or direct) residential share of total emissions was 23%, mostly from petroleum-based fuels such as heating oil used to fuel furnaces and water heaters. Vermont's electric power sector share of emissions from petroleum was only 0.2%, as very little of the state's electricity in 2013 was generated from petroleum or any other fossil fuels. Hawaii, on the other hand, has very little direct use of petroleum for residential heating but much higher use of petroleum for power generation.